1. Field of the Invention
The present invention relates generally to a film splicer for splicing the foremost ends of two films, especially tape automatic bonding films (hereinafter referred to simply as TAB films to each other with the aid of an adhesive tape serving as bonding means. More particularly, the present invention relates to improvement of a tape splicer of the foregoing type which assures that each tape splicing operation can correctly be achieved not only at a high efficiency but also at a high accuracy.
2. Description of the Related Art
An information recording film splicer has been heretofore practically used for the purpose of cutting and splicing a picture film, an information tape or the like. Among a plurality of conventional film splicers, an information recording film splicer includes as essential components a base platform having a guide member and a roll mounted thereon and an arm member adapted to be turnably raised and lowered on the base platform with the base end of the arm member pivotally secured to the base platform, in order to assure that the foremost ends of information recording tapes are brought in contact with each other at a predetermined position with unnecessary parts of the information recording tapes preliminarily cut off from the latter, and moreover, an adhesive tape is adhesively secured to both the information recording tapes along the foremost cut ends of the latter, as disclosed in an official gazette of Japanese Patent Laid-Open Publication NO. 62-86592. As the adhesive tape is drawn from a roll of adhesive tape, it is located above the information recording tape, and thereafter, the arm member is turnably thrust against the upper surface of the base platform by actuating a handle with an operator's hand so as to allow the information recording tape on the guide member to be depressed by a depressing plate attached to the lower surface of the arm member. Subsequently, the adhesive tape is cut at a predetermined position by actuating adhesive tape cutters located at the fore and rear ends of the depressing plate, and thereafter, two information recording tapes cut in that way are spliced to each other using a thin adhesive tape interposed therebetween for the purpose of performing a so-called film editing operation.
In recent years, a tape automatic bonding technique (hereinafter referred to as a TAB technique) is widely employed in many industrial fields as a method of installing integrated circuits on a printed circuit board for producing electronic calculators, electronic watches or clocks, liquid crystal monitors, computers or the like. The TAB technique is typically exemplified by a method of sequentially forming a plurality of wiring patterns on a long film corresponding to integrated circuits and then bonding lead wires extending from the wiring patterns to the corresponding terminals of the integrated circuits. Before and after the integrated circuits are installed on the printed circuit board, a TAB film is visually inspected so that a part of the TAB film including wiring patterns each having incorrect wiring and incorrect bonding detected thereon is removed by actuating a cutter and the remaining acceptable part of the TAB film is spliced to the opponent one in the same manner as the information recording tape editing operation to provide a single long film. With the conventional film splicer constructed in the above-described manner, an adhesive tape is adhesively attached merely to one surface of each of two tapes along the contact line where the foremost ends of the two tapes come in contact with each other. Thus, there sometimes arises a malfunction that both the tapes are parted away from each other, i.e., away from the joint line therebetween depending on how a certain high intensity of pulling power is applied to the tapes.
In view of the foregoing malfunction, a proposal was made with respect to a method of allowing the contact part between two tapes to be clamped between two halves of a folded adhesive tape which in turn is adhesively secured to the two tapes, and thereafter, cutting off an extra part of the adhesive tape by actuating a cutter or the like wherein the foregoing method was practically employed in the past for splicing 16 mm picture films to each other. With the proposed method, a long film having a plurality of film segments sequentially spliced to each other exhibits a high strength because the adhesive tape is adhesively secured to both the surface of the tape. However, since the folded part of the adhesive tape is projected outside of the film on the one side of the latter, it is liable of becoming an obstacle in the course of each film handling operation. For this reason, practical employment of the proposed method is not acceptable when two TAB films are spliced to each other.
To solve the foregoing problem, it is thinkable that two conventional film splicer are employed for TAB films. In this case, a first film splicer serves to allow an adhesive tape to be adhesively secured to a joint part between two TAB films. Subsequently, the adhesive tape is cut away from the joint part, and thereafter, the TAB films are turned upside down so that the original lower surfaces of the same are oriented in the upward direction. Then, a second film splicer serves to allow another adhesive tape to be adhesively secured to the foregoing joint part in the same manner as the first film splicer. However, since it is practically difficult to turn the TAB tapes upside down while they are linearly delivered to both the film splicers, it is thinkable from the viewpoint of practical use that the TAB films are successively delivered to the first film splicer and the second film splicer while they are displaced along a S-shaped path. However, to prevent circuit components such as integrally circuits or the like installed on a printed circuit board from being damaged or injured, the TAB films should basically be bent only in one direction. For this reason, it is not acceptable that they are bidirectionally bent. In addition, when two adhesive tapes are separately adhesively secured to the TAB films with the aid of two film splicers and an extra part of each adhesive tape is then cut off, the outer cut ends of the upper and lower adhesive tapes are usually positionally offset from each other. Thus, a part of the adhesive surface of each adhesive tape appears on the outer surface of each TAB film. However, this is not acceptable.
To solve the foregoing problem, an applicant common to the present invention has proposed a film splicer as disclosed in an official gazette of Japanese Patent Laid-Open Publication NO. 4-5022. According to the prior invention, the film splicer includes a first splicer for bringing the foremost ends of films to be spliced to each other in contact with each other, adhesively securing an adhesive tape to the upper surfaces of the films along the contact line therebetween and then cutting the foremost end part of the adhesive tape and a second splicer for adhesively securing another adhesive tape to the lower surfaces of the films along the contact line therebetween and then cutting the foremost end part of the adhesive tape. The distance between two tape receiving portions for receiving an adhesive tape not only before a guide member of the first splicer but also after the guide member of the same and the distance between blades of two cutters for cutting the foremost end parts of the adhesive tapes are determined to be slightly smaller than a width of each film, while the distance between two tape receiving portions for receiving another adhesive tape not only before a guide member for the second splicer but also after the guide member of the same and the distance between blades of two cutters for cutting the foremost end parts of the adhesive tapes are determined to be approximately equalized to the width of each film.
However, since the film splicer proposed by the applicant as disclosed in the official gazette of Japanese Patent Laid-Open Publication NO. 4-5022 includes two splicers in the combined state, a wide space is required for installing the two splicers on the film splicer. This leads to the result that the film splicer should be improved in respect of reduction of the space required for installing the two splicers, and moreover, the film splicer should be improved in respect of a cost required for installing the film splicer.
In addition, since the adhesive tapes are adhesively secured not only to the upper surfaces of the two tapes but also to the lower surfaces of the same with the aid of the two splicers, an adhesive tape cutting operation should twice be performed for the adhesive tapes with the result that the film splicer should additionally be improved in respect of an operational efficiency.
When an adhesive tape is drawn in the second splicer while the adhesive surface of the same is oriented in the upward direction, there arises a necessity for taking care so as not to allow the adhesive tape to be erroneously adhesively secured to the film after completion of adhesive securing of another adhesive tape to one surface of the film.